Processing cabinet with sub-door access

Abstract

The main door of a freeze dryer is provided with a sub-opening arranged to register with the space between adjacent vertically adjustable freeze dryer shelves, for infeeding and outfeeding trays or other containers of material to and from each shelf. An entry chamber surrounds the sub-opening and has a sloping outer face provided with a resilient seal arranged to form a pressure tight seal with a sub-door movable by a fluid pressure piston-cylinder unit between positions opening and closing the entry passageway of the entry chamber. Photoelectric safety mechanism is associated with the entry passageway to prevent closing of the sub-door when any object is in the entry passageway.

Having now described my invention and the manner in which it may be used, I claim: 
     
       1. In combination, a cabinet having a main closure door, (a) an access sub-opening in the main door configured to permit access to the interior of the cabinet through the main door when the latter is closed,   (b) an entry chamber mounted on the outside of the main door and surrounding the sub-opening, forming an entry passageway registering with the sub-opening and having a sloping outer face,   (c) a sub-door mounted on and spaced outwardly from the main door for movement across the outer face of the entry chamber to open and close said sub-opening,   (d) sealing means interposed between the entry chamber and sub-door and comprising a resilient seal surrounding said entry chamber sloping outer face, the sub-door having a sloping face arranged to abut the resilient seal and form a pressure tight seal therewith when the sub-door is in closed position, and   (e) power means interengaging the main door and sub-door and operative to move the sub-door relative to the entry chamber to open and close the access sub-opening.   
     
     
       2. The combination of claim 1 wherein the cabinet houses a plurality of shelves movable vertically to position adjacent pairs of shelves at a spaced apart loading and unloading position, and the sub-opening is located in the main door for registration with said shelf loading and unloading position. 
     
     
       3. The combination of claim 2 wherein the sub opening in the main door is substantially the same height and width as the space between adjacent shelves at the loading and unloading position. 
     
     
       4. The combination of claim 1 wherein the power means comprises a fluid pressure piston-cylinder unit. 
     
     
       5. The combination of claim 1 including safety means mounted on the main door and registering with the entry passageway and operatively associated with the power means to prevent operation of said power means to move the sub-door to closed position when any object is present in the entry passageway. 
     
     
       6. The combination of claim 5 wherein the safety means comprises photoelectric light source and detector means spanning the space across the entry passageway.